Abstract： AIM:To invent one biodegradable biliary duct stem which spends long degradable time based on our previous research. METHODS:By changing the component methods of the material PLLA and PLGA repeatedly, we invent 3 groups of biliary duct stents named A, B and C. All of them have different degradable time and are obscure to X-ray. Then, we put the stents into the glass tubes which contains fresh human bile, keep them at 37℃ in water bathing tank of constant temperature and shake them at even speed. Observing the stents' change every other 10 d. RESULTS:The stents which are made from PLLA and PLGA(50L/50G)with the weight proportion at 70:30 and 90:10 show long degradation time and excellent strength character.CONCLUSION:We can invent the ideal degradable biliary duct stent through the way of changing the proportion and the composing technology between PLLA and PLGA.